Skills | Techniques & Best Practices


Outboard Flushing,
The Right Way

By John Tiger

It sounds simple, but hang on! There's a right and a wrong way to perform this essential task.

Photo of flushing an outboard with fresh water
Photo: John Tiger
The buildup of salt in your outboard can cause blockages that
result in overheating and eventual corrosion.

Back in the day, flushing an outboard with fresh water was done only one way. A set of "ear muffs" or "flush muffs" was fitted around the engine's gearcase to cover the water intakes, connected to a garden hose with a good water supply, and the engine was run for five to 10 minutes. But today's outboards can be flushed using other, sometimes easier methods, without even starting the engine.

Why Flush?

Salt and brackish water is a corrosive killer of the aluminum from which outboards are made, so flushing every time after saltwater use is a must. Left unchecked inside the cooling passages, saltwater will quickly build up and may cause cooling blockages, leading to overheating and, over time, can corrode an engine from inside out. All outboard manufacturers recommend flushing (according to the procedures outlined in the engine owner's manual) after every use in salt, brackish, dirty, or polluted waters. Operating an engine in sandy, silty, or muddy fresh water also dictates the need for periodic flushing.

1 | 2 | 3 | Next Page


 Recommended Articles
Gray rule

Thumbnail photo of a shut-off lanyard4 Steps To Take If Your Outboard Quits

You're putt-putting along pretty as you please, when suddenly your outboard dies. Major bummer!

Thumbnail photo of testing Torqueedo Travel 1003The Latest On Alternative Outboards

Foundation Findings #52: Our team takes a close look at how environmentally friendly outboard motors perform

Thumbnail photo of checking engine temperatureBoat Engine Troubleshooting

What's that funny smell? Do you hear a strange noise? Stop and trust your senses

BoatUS Magazine Is A Benefit Of BoatUS Membership

Membership Also Provides:

  • Subscription to the print version of BoatUS Magazine
  • 4% back on purchases from West Marine stores or online at
  • Discounts on fuel, transient slips, repairs and more at over 1,000 businesses
  • Deals on cruises, charters, car rentals, hotel stays and much more ...
  • All For Only $24 A Year!

Join Today!